Recent semiconductor devices have been increasingly smaller and highly integrated. To respond to this change, flip chip mounting using a semiconductor chip having a projected electrode (bump) made of a material such as solder is often used. For example, Patent Literature 1 describes a production method for a semiconductor device in which a bump electrode in a semiconductor device is electrically connected to a terminal electrode in a substrate, and a sealing material is injected into a gap between the semiconductor device and the substrate.
Patent Literature 1 aims to pursuit the limit of the viscosity and thixotropic properties needed to obtain good sealing properties of the sealing material. As described in Patent Literature 1, if the sealing material is a composition whose viscosity is 100 Pa·s or less and thixotropic index is 1.1 or less, the sealing material can be sufficiently injected into a narrow gap quickly without producing air bubbles in injecting the sealing material.
Patent Literature 2 describes a curable underfill bonding composition containing surface-treated nanoparticles as an underfill material in which the nanoparticles are substantially spherical, non-agglomerated, amorphous, and solid. As described in Patent Literature 2, use of the surface-modified nanoparticles attains an underfill adhesive having a desirable coefficient of thermal expansion (CTE) and providing useful viscosity ranges for use of capillary underfill processes.
Unfortunately, the size of the semiconductor chip has been smaller and smaller, leading to a narrower pitch between bumps these days. Accompanied by these, the gap between semiconductor chips or the gap between the semiconductor chip and the substrate has also become narrower. For this reason, the air is easily contained in the sealing resin (underfill) in injecting the sealing resin, resulting in occurrence of voids.
In order to solve the problem, for example, methods have been examined in which a sealing resin is applied in advance in a bonding area, instead of the method in which a sealing resin is injected into the gap after electrodes are bonded. For example, Patent Literature 3 describes a production method for a semiconductor device in which a predetermined liquid sealing resin composition is applied to a position in a circuit on the surface of an inorganic substrate or organic substrate at which a semiconductor element is to be mounted; an electrode of the semiconductor element is bonded to a circuit on the substrate with bumps being interposed therebetween, and at the same time, the liquid sealing resin composition is cured.
Unfortunately, even the method according to Patent Literature 3 cannot sufficiently eliminate the possibility of occurrence of voids. Moreover, in the method according to Patent Literature 3, the sealing resin easily wicks up to the upper surface of the semiconductor chip to contaminate an attachment of a bonding apparatus. Furthermore, voids occur easily, for example, when the underfill material according to Patent Literature 2 is used in the method according to Patent Literature 3.